Apparatus for annealing sheet glass



Jan. 8,1929. 1,698,479

V. MULHOLLAND APPARATUNS. FOR ANNEALING SHEET eLAss- Filed Oct. 14, 1926i=1- v 4 1120612101" 6 il zzwuzhzmz {3%{5 y mm mm,

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Patented Jan. 8, 1929.

Ll NlTED STATES PATENT OFFICE."

VERGIL MULHOLLAND, OF WEST HARTFORD, CONNECTICUT, ASSIGNOR TO HARTFORD-EMPIRE COMPANY, OF HARTFORD, CONNECTICUT, A. CORPORATION OF DELAWARE.

APPARATUS FOR ANNEALING- SHEET GLASS.

Application filed October 14, 1926. Serial No. 141,631.

This invention relates to apparatus for annealing sheet glass and it hasparticular relation to lehrs of the tunnel type, through which sheets;or continuous strips of glass are transported by a conveyor, and inwhich they are subjected to varying temperature environments, in orderto relieve stresses and strains that may exist in the glass.

One of the objects of this invention is to provide a lehr in which boththe upper and the lower surfaces of the sheet glass will be subjedtedtoa uniform temperature at any given cross sectional portion of thetunnel, and in which the temperature above and be low the glass may beeasily regulated throughout the entire length of the tunnel. Briefly,this temperature control is obtained by providing a tunnel lehr havingtwo separate and independent fire boxes, one above and one beneath thereceiving end of the tunnel, and communicating respect1vely with heatingflues extending longitudinally above and beneath the tunnel. Thetemperature in each of these flues is regulated at will bydamper-controlled openings through which air from the outer atmospheremaybe admitted into the flues in regulable quantities to dilute and coolthe heated gases passing therethrough.

In the accompanying drawings:

Figure 1 is a diagrammatic longitudinal section through a tunnel lehrconstructed in accordance with the invention;

Fig. 2 is a vertical transverse sectional view,

on a larger scale, taken on. line 22 of Fig. 1, and illustrating themethod of connecting the flues-"to a common suction device;

Fig. 8 is a similar view taken on line 33 of Fig. 1 and illustrating theconstruction of the damper-controlled openings in the flues, and

Fig. 4 is a vertical longitudinal sectional view through a. portion ofthe tunnel and illustrating the baflie plates for minimizing the draftabove the glass.

Referring to the drawings, a relatively wide and low lehr tunnel 1 isillustrated as being constructed of a plurality of substantially similarmetallic sections 2 arranged in end-to-end relation. The tunnel sectionsare mounted on rollers 3 which ride on rails 4 carried by a plurality ofpedestals 5. By

, neath the lehr and is supported by rollers 7 The conveyor 6 may be ofany preferred construction and may be driven by any suitable mechanismindicated at 8, Fig. 1.

Heating flues 9 and 10, respectively, extend longitudinally above andbeneath the tunnel and respectively communicate, through dampercontrolled passageways 11 and 12,

with the boxes 13 and 14 disposed one above and one beneath thereceiving end of the lehr. A plurality of damper-controlled openings orstacks 15 and 16 are disposed at intervals longitudinally of the flues 9and 10, respectively, and establish communication between these fluesand the outer atmosphere.

Heated gases from the fire boxes 13 and 14 are drawn through the flues 9and 10 by means of a common suctionv device 17, which communicates withthe upper flue 9 through a damper-controlled passageway 18 and with thelower flue 10. through a damper-controlled passageway 19 and a pair ofpipes 20 disposed one on each side of the tumiel. This suction devicemay be of any preferred construction but is herein shown as comprising amotor-driven suction fan. Heat is prevented from dissipating too rapidlyfrom the flues and from the tunnel by means of a suitable casing 21 ofinsulating material.

By suitably adjusting the dampers in the passageways 11, 12, 18 and 19,the draft in the flues 9 and 10 may be regulated at will a tendency fora current of air to flow through the tunnel above the glass and todisturb the desired heat conditions therein. WVhile this difficulty maybe partly compensated for by supplying more heat to the upper flues thanto the lower, it may be found desirable 'to equip the tunnel with apluralityof transversely extending baflie plates or partitions 22, Fig.4, which depend from the top of the tunnel and are arranged at intervalstherealong. These baflies are preferably cast integral with the top wallof the tunnel and extend downwardly to a point adjacent to the glass,suflicient clearance being provided to prevent them from contacting withthe glass when they expand under the influence of heat.

The draft above the glass is thereby re- Y duced to that which may passthrough the relatively small spaces between the upper surface of theglass and the lower edges of the baflies 22. The air in the spacesbetween the battles is in a substantially static condition and retainsthe temperature of the adjacent portions of the heating flue.

-- By means of the above-described construction, a uniform temperaturemay be readily of the invention as defined in the appended claims.

I claim as my invention 1. Apparatus for annealing sheet glass,comprising a tunnel, means for transporting sheet glass therethrough, aheating flue extending longitudinally above said tunnel andcommunicating with a fire box located above the receiving end thereof, aheatin flue extending longitudinally beneath said tunnel andcommunicating with a fire box located beneath the receiving end thereof,and means,

located at intervals longitudinally of each of said flues forcontrolling the temperatures in different zones of said tunnel.

2. Apparatus for annealing sheet glass, comprising a tunnel, means fortransporting sheet glass therethrough, a heating flueextendinglongitudinally above said tunnel and communicating with a fire boxlocated above the receiving end thereof, a heating flue ex--.

tending longitudinally beneath said tunnel and communicating with a firebox located beneath the receiving end thereof, and means located atintervals longitudinally of each of said flues for admitting atmosphericair into said flues to control the temperatures in diiferent z ones ofsaid tunnel.

3. Apparatus for annealing sheet glass, comprising a tunnel, means fortransporting sheet glass therethrough, a heating flue extendinglongitudinally above said tunnel and communicating with a fire boxlocated above the receiving end thereof, a heating flue extendinglongitudinally beneath said tunnel and communicating with a fire boxlocated beneath the receiving end thereof, and means located atintervals longitudinally of each of said flues for admitting atmosphericair in regulable quantities into said flues to control the temperaturesin different zones of said tunnel.

4. Apparatus for annealing sheet glass, comprising a tunnel, means fortransporting sheet glass therethrough, a heating flue ex-.

tending longitudinally above said tunnel and communicating with a firebox located above the receiving end thereof, a heating flue extendinglongitudinally beneath said tunnel and communicating with a fire boxlocated beneath the receiving end thereof, a single suction devicecommunicating with both of said flues for drawing heated gases from saidfire box through said flues at subatmospheric pressure, and meanslocated at intervals long'itudinally of each of said flues forcontrollingthetemperatures in diiferent zones of said tunnel.

.5. Apparatus for annealing sheet glass, comprising a metallic tunnel,means for transporting sheet glass therethrough, a flue extendinglongitudinally above said tunnel, the top wall of said tunnelconstituting the bottom wall of said flue, a the box disposed above thereceiving end of said tunnel and communicating with said upper flue, aheating flue extending longitudinally beneath said tunnel, the bottom ofsaid tunnel constituting the upper wall of said lower flue,

a fire box located beneath the receiving end of said tunnel andcommunicating with said lower flue, means for causing the flow of heatedgases through both ofsaid flues at subatmospheric pressure, and a seriesof dampercontrolled-openings disposed at intervals longitudinally ofeach of said flues for admitting regulable quantities of air from theouter atmosphere into said flues to dilute and cool the hot gasespassing therethrough and to thus independently control the temperaturesin diiierent zones longitudinally of said flues and tunnel,

6. Apparatus for annealing sheet glass comprising a tunnel, means fortransporting sheet glass. therethrough, similar longitudicomprising atunnel, means for transporting sheet glass therethrough, similarlongitudinal heating fines respectively above and below said tunnel,similar fireboxes communicating respectively With said fines at pointsopposite one another, similar means for each flue spaced at intervalstherealong for controlling the temperatures therein, whereby the heatconditions above and below the glass may be separately controlled, andmeans to lo Withdraw the heating media from said fines.

Signed at Hartford, Conn, this 13th day of October,

1926- VERGIL MULHOLLAND.

